Osteotomy combined with anterior cruciate ligament reconstruction for anterior cruciate ligament injury and biplanar deformity.

BACKGROUND: It has been confirmed that the increased posterior tibial slope over 12 degrees is a risk factor for anterior cruciate ligament injury, and varus deformity can aggravate the progression of medial osteoarthritis. AIM: To evaluate the efficacy of modified high tibial osteotomy (HTO) and anterior cruciate ligament reconstruction (ACLR) in the treatment of anterior cruciate ligament (ACL) injuries with varus deformities and increased posterior tibial slope (PTS) based on clinical and imaging data. METHODS: The patient data in this retrospective study were collected from 2019 to 2021. A total of 6 patients were diagnosed with ACL injury combined with varus deformities and increased PTS. All patients underwent modified open wedge HTO and ACLR. The degree of correction of varus deformity and the PTS was evaluated by radiography and magnetic resonance imaging. RESULTS: All 6 patients (6 knee joints) were followed up for an average of 20.8 ± 3.7 months. The average age at surgery was 29.5 ± 3.8 years. At the last follow-up, all patients resumed competitive sports. The International Knee Documentation Committee score increased from 50.3 ± 3.1 to 87.0 ± 2.8, the Lysholm score increased from 43.8 ± 4.9 to 86 ± 3.1, and the Tegner activity level increased from 2.2 ± 0.7 to 7.0 ± 0.6. The average movement distance of the tibia anterior translation was 4.8 ± 1.1 mm, medial proximal tibial angle (MPTA) was 88.9 ± 1.3° at the last follow-up, and the PTS was 8.4 ± 1.4°, both of which were significantly higher than those before surgery (P < 0.05). CONCLUSION: Modified open wedge HTO combined with ACLR can effectively treat patients with ACL ruptures with an associated increased PTS and varus deformity. The short-term effect is significant, but the long-term effect requires further follow-up.

Evaluation of Tibial Slope on Radiographs in Pediatric Patients With Tibial Spine Fractures: An Age- and Sex-Matched Study.

Background: A recent study has reported that the radiographic measurement of posterior tibial slope (PTS) is larger in male pediatric patients with tibial spine fractures (TSF) than in controls. However, they found no difference in PTS between female patients and controls. Purpose: (1) To identify whether PTS is larger in female pediatric patients with TSF than in female controls and (2) to validate the relationship between PTS and pediatric TSF in male patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: After an a priori power analysis, 84 pediatric patients with TSF (50 female patients and 34 male patients) and 84 age- and sex-matched controls were enrolled in this study. Demographic information, including sex, age, and race, was recorded. Skeletal maturity was determined based on the stage of epiphyseal union on knee radiographs. PTS was defined as the angle between a line perpendicular to the longitudinal axis of the tibia and the posterior inclination of the medial tibial plateau on standard knee lateral radiographs. Results: The mean age when the TSF occurred was 11.2 ± 2.7 years for female patients and 12.9 ± 2.5 years for male patients. There was no significant difference in skeletal maturity between female patients and female controls or between male patients and male controls. The mean PTS was not significantly different between female patients (8.8°± 2.8°) and female controls (8.3°± 3.1°) (P = .366) or between male patients (9.0°± 2.8°) and male controls (9.3°± 2.6°) (P = .675). Those with a PTS >1 SD (2.9°) above the mean (8.8°) had no greater odds (1.0 [95% CI, 0.4-2.5]; P≥ .999) of having a TSF than others. Conclusion: PTS was not found to be a risk factor for pediatric TSF in female or male patients in this study.

The influence of tibial length on radiographic posterior tibial slope measurement: How much tibia do we need?

PURPOSE: The purpose of this study was to determine whether significant differences exist when comparing posterior tibial slope (PTS) measured using increasing lengths of the tibia to determine the anatomical axis. METHODS: Patients with full-length weight-bearing tibial radiographs were retrospectively identified from 2014 to 2022 at a single institution. Patients were excluded if there was any previous history of lower extremity fracture or osteotomy. The anatomical axis of the tibia was determined using the full length of tibial radiographs, and the "reference PTS" was measured using this axis. Using the same radiograph, the PTS was measured using four different anatomical axes at standardized tibial lengths. While the center of the proximal circle remained constant at 5-cm below the tibial plateau, the center of the distal circle was drawn at four points: a) overlapping circles; b) 10-cm distal to the tibial plateau; c) 15-cm distal to the tibial plateau; d) half the length of the tibia, measured from the tibial plateau to the tibial plafond. Bivariate correlation and frequency distribution analysis (measurements >2-degrees from reference PTS) were performed between the reference PTS and PTS measured at each of the four other lengths. RESULTS: A total of 154 patients (39.8 ± 17.4 years old, 44.2% male) were included in the final analysis. Measurements at each of the four tibial lengths were all significantly different from the reference PTS (p < 0.001). The correlation strength improved with increasing tibial length (overlapping: R = 0.681, 10-cm: R = 0.821, 15-cm: R = 0.937, and half-tibia: R = 0.963). The number of PTS measurements >2-degree absolute difference from the reference PTS decreased with increasing tibial length (overlapping: 40.3%, 10-cm: 24.0%, 15-cm: 26.0%, and half-tibia: 18.8%). CONCLUSION: Assessment of PTS is dependent on the length of the tibia utilized to obtain the anatomical axis. Accuracy and precision of PTS measurements improved with increasing length of tibia used to determine the anatomical axis. STUDY DESIGN: Case series.

Variability Between Full-Length Lateral Radiographs and Standard Short Knee Radiographs When Evaluating Posterior Tibial Slope in Revision ACL Patients.

Background: Increased posterior tibial slope (PTS) has been identified as a risk factor for failure after anterior cruciate ligament (ACL) reconstruction. Correction of PTS may improve outcomes after revision ACL reconstruction. There are conflicting reports demonstrating the measurement of the PTS on standard short knee (SSK) radiographs versus full-length lateral (FLL) radiographs including the entire tibia. Purpose/Hypothesis: To compare PTS measurements between SSK and FLL radiographs in patients who failed primary ACL reconstruction. It was hypothesized that there would be high variability between the SSK and FLL radiographic measurements. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The medial and lateral PTS were measured on the SSK and FLL radiographs of 33 patients with failed primary ACL reconstructions. All measurements were performed by 2 trained independent observers (A.A.M., J.S.), and inter- and intraobserver reliability were calculated using the intraclass correlation coefficient (ICC). Measurements recorded by the observer with the higher intraobserver ICC were used for comparison of the PTS on SSK versus FLL radiographs. Results: Both the inter- and the intraobserver reliability values of the PTS measurements were excellent. There was a significant difference in mean PTS on the medial plateau as measured on the SSK and FLL radiographs (11.2°± 5.3° vs 12.5°± 4.6°; P = .03), with the FLL radiographs demonstrating higher PTS. There was also a significant difference in the mean PTS on the lateral plateau as measured on SSK versus FLL radiographs (10.7°± 4.3° vs 12.2°± 4°, respectively; P = .01), with the FLL radiographs demonstrating higher PTS. Notably, 66.67% of the absolute measurements for PTS on the medial plateau differed by ≥2°, with variability as high as 8.5°. Conclusion: Results indicated that FLL and SSK radiographs are not interchangeable measurements for PTS associated with failed ACL reconstruction. Because FLL radiographs demonstrate less variability than SSK radiographs, we recommend obtaining them to evaluate these complex patients.

Clinico-Radiological Correlation Between Anterior Cruciate Ligament Deficiency and Hyperextension of the Knee Joint: A Prospective Study.

INTRODUCTION: The anterior cruciate ligament (ACL) primarily restricts anterior sliding of the tibia over the fixed femur, thereby also postulating to prevent hyperextension of the knee joint. The main objective of our study was to identify the role of the ACL in the prevention of knee hyperextension and to quantify the amount of hyperextension caused by an ACL tear, apart from its well-established role in the prevention of anterior tibial translation on the fixed femur. METHODS:  This prospective study was conducted in a tertiary care hospital. Eighty patients with unilateral ACL tears were assessed clinico-radiologically in the preoperative period to quantify the knee hyperextension, which was then compared with the uninjured contralateral knee of the same patient. Posterior tibial slope and notch width index were also assessed to rule out bias in our study. RESULTS: The mean age of patients in our study was 27.3 years. Out of 80 patients, 70 were male and 10 were female. The Pearson coefficient for clinically and radiologically assessed hyperextension was 0.919 (p-value 0.001) and 0.910 (p-value 0.001), respectively. Posterior tibial slope and notch width index assessment showed Pearson coefficients of -0.018 (p-value 0.887) and -0.068 (p-value 0.547), respectively. CONCLUSION: Anterior cruciate ligament complete tear or deficiency produces knee hyperextension, which varies from patient to patient. Though the amount of hyperextension produced is mild (less than five degrees in most patients), it can cause a significant amount of knee instability. Hence, correction of knee hyperextension is crucial while performing ACL reconstruction.

[The correct tibial slope? Comparison of measuring methods]. / Der korrekte tibiale Slope? Messmethoden im Vergleich.

INTRODUCTION: From a biomechanical point of view, the tibial slope plays a significant role in relation to the loading of the ligament structures in the knee joint. Currently, there are various methods of measurement for the tibial slope, which makes it difficult to compare the measurement results obtained. These differences can be decisive factors for the indication and the extent respectively of the correction of the tibial slope. The aim of this work is to present the differences in results between the measurement methods, and to compare these with the posterior tibial slope (PTS). METHODS: By means of a comparative analysis, six measurement techniques for the tibial slope were examined. Using six parameters (correlation coefficient, range, deviation of the average slope value, correction coefficient, difference in the corrected measurements, range of the corrected measurements), these results were compared with the PTS. In this prospective study, the PTS was measured in 107 (49 male, 58 female, age 42.6 ± 23.4 years) strictly lateral plain radiological projections of the tibia with the talocrural joint in comparison with the measurement methods according to Han, Brazier, Moore and Harvey, Pietrini and LaPrade and a supratuberosity measurement. RESULTS: The posterior slope was observed at a mean value of 6.9° (±â€¯8.6°). Compared with the PTS, tibial slope values were increased in 55.5 % of all measurements examined and decreased in 42.4 %. In 2 % the values were identical to those of PTS. The deviations observed were significant at up to +2.9° (±â€¯1.7°) and -2.3° (±â€¯1.5°) respectively in comparison with the measured PTS (p < 0.001). 25.9 % of the results showed a slope value more than 2°too high and 17.6 % one less than -2° too low. Thus, in 43 % of the results clinically relevant results that were too high or too low were observed for the tibial slope compared with the PTS (p < 0.001). The correlation analyses showed very high linear connections with PTS (p < 0.001) for all methods, from r2 = 0.88 (in Moore and Harvey) up to r2 = 0.98 (in Han). The ranges varied between 13.90° (Moore and Harvey) and 18.30° (Han). CONCLUSION: Depending on the measurement method, the slope values obtained should be individually evaluated, in order to draw the correct clinical conclusions. In principle, the radiological assessment of the whole lower leg is essential, so that concomitant pathologies in the area of the entire tibia can be detected. In everyday clinical practice, the measurement according to Han et al., and thus a shorter X­ray projection, makes it possible to draw optimal conclusions about the PTS. LOE: Prospective diagnostic study, Level II.

Effect of plate design on maintenance of anterior and posterior gaps and posterior tibial slope after cyclic loading in medial open-wedge high tibial osteotomy: A biomechanical study using porcine's tibia.

Purpose: We aimed to investigate whether a plate adapted to the anatomy of the proximal medial porcine's tibia would provide maintenance of the anterior gap (AG), posterior gap (PG) and posterior tibial slope (PTS). Methods: Twenty-seven porcine tibias were biomechanically evaluated by performing MOWHTO and placing TOMOFIX (n = 9), AC plate (n = 9) and TriS (n = 9) anteromedially. Cyclic testing (800 N, 2000 cycles, 0.5 Hz) was performed to investigate the PTS over time for MOWHTO. The particular displacement calculated from the maximum to the minimum point with the load-displacement curve along the mechanical axis during cyclic testing, the final AG and PG changes at the osteotomy site, the increased PTS calculated by subtracting AG from PG after 2000 cycles were compared among the three groups. The displacement was evaluated by repeated-measures analysis of variance (ANOVA), and changes in AG and PG and increased PTS were evaluated by one-way ANOVA. The sample size for α and ß errors were <0.05 and <0.20, and the effect size was 0.64 for one-way ANOVA and 0.49 for repeated-measures ANOVA. Results: There were no significant differences in displacement among the groups. A significant difference was observed in the AG (p = 0.044) and PG (p = 0.0085) changes. There were no significant differences in increased PTS among the groups. Conclusion: When anteromedially placed, the AC plate and TriS resulted in significant maintenance of AG and PG compared with that of TOMOFIX in MOWHTO after cyclic loading. Level of Evidence: Level Ⅳ.

Do the Clinical and Radiological Features of Knees with Mucoid Degeneration of the Anterior Cruciate Ligament Differ According to Knee Osteoarthritis Status?

Background: The etiology and pathology of mucoid degeneration of the anterior cruciate ligament (MD-ACL) remain poorly understood. MD-ACL may be associated with knee osteoarthritis (OA) or a mechanism other than OA. This study evaluated the radiological differences between knees with MD-ACL and those with a normal ACL and compared the clinical and radiological features of knees with MD-ACL according to the knee OA status. Methods: This retrospective study compared the radiological features of the intercondylar notch width index (NWI) and posterior tibial slope (PTS) of 67 MD-ACL patients (MD group) and 67 age-, sex-, and OA grade-matched patients with a normal ACL (control group). During the subgroup analysis, MD-ACL patients were divided into the non-OA subgroup (n = 41) and OA subgroup (n = 26). The pain location and characteristics of the knee, PTS, and NWI were compared between these subgroups. Results: Compared to the control group, the MD group had a lower NWI (0.26 ± 0.03 vs. 0.28 ± 0.01, p < 0.001) and a larger PTS (11.3° ± 3.0° vs. 9.2° ± 2.5°, p < 0.001). During the subgroup analysis, the most common pain locations were the posterior and medial aspects of the knee in the non-OA subgroup (43.9%) and OA subgroup (53.8%), respectively. Pain on terminal flexion was the most common pain characteristic in both subgroups (non-OA subgroup, 73.1%; OA subgroup, 53.8%). The PTS was not different between subgroups (11.7° ± 3.2° in the non-OA subgroup vs. 10.6° ± 2.7° in the OA subgroup; p = 0.159). However, the non-OA subgroup had a lower NWI than the OA subgroup (0.25 ± 0.03 vs. 0.28 ± 0.02, p = 0.001). Conclusions: Patients with MD-ACL had a lower NWI and a larger PTS than patients with a normal ACL. Furthermore, the clinical and radiological features of MD-ACL differed according to the knee OA status. A narrow intercondylar notch may be more closely associated with the development of MD-ACL without OA.

Comparison of Clinical and Radiological Outcomes of Total Knee Arthroplasty in Osteoarthritic Patients.

Background The knee is the joint most commonly affected by osteoarthritis, more than any other. Osteoarthritis is a progressive, long-term condition that leads to the deterioration of joint tissue and cartilage, resulting in pain and impairment. Total knee arthroplasty (TKA) is a successful intervention that improves functional capability, decreases pain, and enhances quality of life. We conducted this study to evaluate whether radiological parameters following TKA influence the clinical outcomes of patients with knee osteoarthritis. Methods The study was conducted on patients treated for knee osteoarthritis at the Department of Orthopedics, Rajindra Hospital and Government Medical College, Patiala, Punjab, in collaboration with the Department of Radiology over a period of 1.5 years. A total of 152 patients diagnosed with knee osteoarthritis were included in the study; all underwent TKA. Patients underwent clinical evaluation and were graded using the Knee Society Score (KSS) during follow-up examinations. Pain was evaluated using the Visual Analog Scale (VAS). Postoperative X-rays were obtained, and various angles, including the distal femoral angle (DFA), the proximal tibial angle (PTA), and the posterior slope angle (PSA), were measured. Patient follow-up was conducted at three days, three months, and six months. Subsequently, a comparison of the clinical and radiological outcomes of TKA was performed. Results In this study, a total of 152 patients participated, with the majority falling into the 61-70 age group. Of these patients, 40.13% were female and 59.87% were male. The average medial DFA was 94.05°, the average medial PTA was 89.31°, and the PSA was 6.6°. Patients with a medial DFA of 94.05° (±3), a medial PTA of 89.31° (±3), and a PSA of 6.6° (±3) were categorized into the normal group. Conclusion Patients with DFA, PTA, and PSA in the normal range demonstrate improved KSS and clinical outcomes.

Combined tibial deflexion osteotomy and anterior cruciate ligament reconstruction improves knee function and stability: A systematic review.

IMPORTANCE: Patients with excessive posterior tibial slope (PTS) may have higher risks of anterior cruciate ligament (ACL) reconstruction (ACL-R) failure, and clinical outcomes after revision of ACL-R procedures are typically poor. OBJECTIVE: This study aimed to perform a systematic review of the literature summarizing the clinical and radiological outcomes of the surgical treatment of ACL insufficiency in the setting of excessive PTS using a tibial deflexion osteotomy combined with ACL-R. EVIDENCE REVIEW: A systematic review of the literature was performed using PubMed, Cochrane Library, and OVID Medline databases from 1990 to present. Inclusion criteria were studies of outcomes of isolated tibial deflexion osteotomies performed with primary or revision ACL-R in the English language. Data extracted included study demographic information, type of tibial deflexion osteotomy and concomitant procedures, radiological outcomes, patient-reported outcome scores, and postoperative complications. FINDINGS: Six studies, with 133 knees were identified. All included studies were retrospective case series, with a weighted mean follow-up of 3.39 years. In 106 of 133 (79.7%) knees, tibial deflexion osteotomy was performed concomitantly with an ACL-R, whereas in 27 of 133 (20.3%) knees, the procedures were staged. 22, 45, and 66 of 133 knees (16.5%, 33.8%, and 49.6%) underwent primary, first revision, and second or greater revision ACL-R, respectively. Three of 133 (2.25%) knees demonstrated recurrent ACL graft failure at the final follow-up. On average, PTS decreased from 15.2° preoperatively to 7.1° postoperatively. The mean International Knee Documentation Committee, Lysholm, and Tegner scores increased from 42.5, 46.4, and 4.2 preoperatively to 71.8, 89.0, and 6.7 postoperatively. CONCLUSIONS: The results of this review suggest that combined ACL-R and tibial deflexion osteotomy may be effective in decreasing PTS and improving knee function and stability. STUDY DESIGN: Systematic Review; Level of evidence 4.

Enhanced reliability and time efficiency of deep learning-based posterior tibial slope measurement over manual techniques.

PURPOSE: Multifaceted factors contribute to inferior outcomes following anterior cruciate ligament (ACL) reconstruction surgery. A particular focus is placed on the posterior tibial slope (PTS). This study introduces the integration of machine learning and artificial intelligence (AI) for efficient measurements of tibial slopes on magnetic resonance imaging images as a promising solution. This advancement aims to enhance risk stratification, diagnostic insights, intervention prognosis and surgical planning for ACL injuries. METHODS: Images and demographic information from 120 patients who underwent ACL reconstruction surgery were used for this study. An AI-driven model was developed to measure the posterior lateral tibial slope using the YOLOv8 algorithm. The accuracy of the lateral tibial slope, medial tibial slope and tibial longitudinal axis measurements was assessed, and the results reached high levels of reliability. This study employed machine learning and AI techniques to provide objective, consistent and efficient measurements of tibial slopes on MR images. RESULTS: Three distinct models were developed to derive AI-based measurements. The study results revealed a substantial correlation between the measurements obtained from the AI models and those obtained by the orthopaedic surgeon across three parameters: lateral tibial slope, medial tibial slope and tibial longitudinal axis. Specifically, the Pearson correlation coefficients were 0.673, 0.850 and 0.839, respectively. The Spearman rank correlation coefficients were 0.736, 0.861 and 0.738, respectively. Additionally, the interclass correlation coefficients were 0.63, 0.84 and 0.84, respectively. CONCLUSION: This study establishes that the deep learning-based method for measuring posterior tibial slopes strongly correlates with the evaluations of expert orthopaedic surgeons. The time efficiency and consistency of this technique suggest its utility in clinical practice, promising to enhance workflow, risk assessment and the customization of patient treatment plans. LEVEL OF EVIDENCE: Level III, cross-sectional diagnostic study.

Considerations for revision anterior cruciate ligament reconstruction: A review of the current literature.

Background: Failure rates among primary Anterior cruciate ligament reconstruction range from 3.2 to 11.1 %. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. Methods: The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes, and return to sport (RTS) for patients who undergo revision ACLR. Results: In revision ACLR patients, those receiving autografts are 2.78 times less likely to experience a re-rupture compared to patients who receive allografts. Additionally, individuals with properly positioned tunnels and removable implants are considered strong candidates for one-stage revision procedures. Conversely, cases involving primary tunnel widening of approximately 15 mm are typically indicative of two-stage revision ACLR. These findings underscore the importance of graft selection and surgical approach in optimizing outcomes for patients undergoing revision ACLR. Conclusion: Given the high rates of revision surgery in young, active patients who return to pivoting sports, the literature recommends strong consideration of a combined ACLR + anterolateral ligament (ALL) or lateral extra-articular tenodesis (LET) procedure in this population. Unrecognized posterolateral corner (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Consider revision ACLR with combined slope-reducing tibial osteotomy in cases of posterior tibial slope greater than 12°.

Tibiofemoral bone configuration is not associated with hamstring muscle strength in male and female patients with ACL reconstruction.

PURPOSE: Previous evidence indicated that the tibiofemoral bone configuration might elevate the risk of an anterior cruciate ligament (ACL) injury. Furthermore, a low hamstring-to-quadriceps muscle ratio predisposes especially females to unfavourable knee kinematics. The primary objective of the present study was to investigate sex-specific associations between tibiofemoral bone geometry and isokinetic knee flexion torque in patients with primary ACL injury followed by ACL reconstruction. METHODS: N = 100 patients (72 = male, 28 = female, age = 31.3 ± 10.2, body mass index = 25.3 ± 3.6) with primary ACL rupture with isokinetic knee flexion torque assessments before and 6 months after ACL reconstruction surgery were analysed. Magnetic resonance imaging scans were analysed for medial posterior tibial slope (MPTS) and lateral posterior tibial slope, notch width index (NWI) and lateral femoral condyle index (LFCI). Additionally, isokinetic knee flexion torque (60°/s) and hamstring-quadriceps ratios were evaluated. Subsequently, functional parameters were correlated with imaging data for gender subgroups. RESULTS: The findings showed that presurgical isokinetic knee flexion torque was not associated with any marker of femoral or tibial bone geometry. Further, while significant differences were observed between female (0.883 ± 0.31 Nm/kg) and male (1.18 ± 0.35 Nm/kg) patients regarding preoperative normalized knee flexion torque (p < 0.001), no significant sex differences were found for percentage increases in normalized knee flexion torque from presurgery to postsurgery. Generally, female patients demonstrated significantly higher MPTS magnitudes (p < 0.05) and lower LFCI values (p < 0.05) compared to men. CONCLUSION: The present results demonstrated no association between tibial or femoral bone geometry and muscle strength of the hamstrings in patients with ACL reconstruction, indicating an important mismatch of muscular compensation to deviations in bone geometry. There were no sex-specific differences in tibiofemoral bone parameters. LEVEL OF EVIDENCE: Level III.

Comparison of Side-to-Side Difference in Posterior Tibial Slope in Knees With Acute Versus Chronic Anterior Cruciate Ligament Deficiency.

Background: The posterior tibial slope (PTS) is an important feature in knee joint biomechanics and indicates anterior-posterior knee stability. Increased PTS is a known risk factor for both primary anterior cruciate ligament (ACL) rupture and postreconstruction rerupture. Purpose: To investigate the effect of long-term exposure to ACL deficiency on the PTS and the sagittal anatomy of the proximal tibia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 44 patients (38 men, 6 women) with a history of knee injury and ACL rupture confirmed by magnetic resonance imaging and physical examination were included in this study. Patients were divided into those with chronic ACL deficiency (group 1: injured ≥5 years prior; n = 22) and acute ACL deficiency (group 2: injured <1 year prior; n = 22). The medial and lateral tibial plateau PTS and anterior tibial translation were measured on monopodal weightbearing knee radiographs at 20° of flexion. The mechanical tibiofemoral angle (MTFA) and the medial proximal tibial angle (MPTA) were measured using an orthoroentgenogram. The side-to-side difference between the affected and unaffected knees was also calculated for all measurements. Results: The mean duration of exposure to ACL deficiency was 7.6 years (range, 5-15 years) in group 1 and 4.4 months (range, 1-11 months) in group 2. Regarding the side-to-side differences in angular measurements, a higher medial PTS (affected vs unaffected: 12.4° vs 10.1°; P = .007), higher lateral PTS (11° vs 8.9°; P = .011), and increased varus alignment on both the MTFA (4.3° vs 2.4°; P = .036) and the MPTA (84.9° vs 86.3°; P = .033) were found in group 1, while no significant differences in angular measurements were found in group 2. Compared with group 2, patients in group 1 had a significantly higher side-to-side difference in the medial PTS (2.3° vs 0.1°; P = .0001), lateral PTS (2.1° vs 0.4°; P = .0001), and MPTA (1.4° vs 0.1°; P = .002). Conclusion: This study showed that the affected knees of patients with chronic ACL deficiency (≥5 years) had higher medial and lateral PTS compared with the unaffected contralateral knees. Therefore, when planning ACL reconstruction for patients with a history of long-term ACL deficiency, it is crucial to measure the preoperative PTS accurately.

Evaluation of Failed ACL Reconstruction: An Updated Review.

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Posterior tibial slope influences joint mechanics and soft tissue loading after total knee arthroplasty.

As a solution to restore knee function and reduce pain, the demand for Total Knee Arthroplasty (TKA) has dramatically increased in recent decades. The high rates of dissatisfaction and revision makes it crucially important to understand the relationships between surgical factors and post-surgery knee performance. Tibial implant alignment in the sagittal plane (i.e., posterior tibia slope, PTS) is thought to play a key role in quadriceps muscle forces and contact conditions of the joint, but the underlying mechanisms and potential consequences are poorly understood. To address this biomechanical challenge, we developed a subject-specific musculoskeletal model based on the bone anatomy and precise implantation data provided within the CAMS-Knee datasets. Using the novel COMAK algorithm that concurrently optimizes joint kinematics, together with contact mechanics, and muscle and ligament forces, enabled highly accurate estimations of the knee joint biomechanics (RMSE <0.16 BW of joint contact force) throughout level walking and squatting. Once confirmed for accuracy, this baseline modelling framework was then used to systematically explore the influence of PTS on knee joint biomechanics. Our results indicate that PTS can greatly influence tibio-femoral translations (mainly in the anterior-posterior direction), while also suggesting an elevated risk of patellar mal-tracking and instability. Importantly, however, an increased PTS was found to reduce the maximum tibio-femoral contact force and improve efficiency of the quadriceps muscles, while also reducing the patellofemoral contact force (by approximately 1.5% for each additional degree of PTS during walking). This study presents valuable findings regarding the impact of PTS variations on the biomechanics of the TKA joint and thereby provides potential guidance for surgically optimizing implant alignment in the sagittal plane, tailored to the implant design and the individual deficits of each patient.

Around-the-knee osteotomies part II: Surgical indications, techniques and outcomes - State of the art.

Recent advances in surgical techniques and planning for knee-based osteotomies have led to improvements in addressing lower extremity malalignment. Part 1 of this review presented the biomechanical and clinical rationale of osteotomies, emphasizing the importance of osteotomies for restoring normal knee kinematics. In Part 2 of this review, indications, surgical technique and outcomes of osteotomies to correct coronal, sagittal and axial plane deformities will be examined. Traditional high tibial and distal femoral osteotomies will be discussed in addition to more recent advanced techniques including biplanar corrections and double-level osteotomies, as well as slope-correcting osteotomies. Patient-specific instrumentation and its use in more complex corrections will also be addressed.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study.

OBJECTIVE: Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques. METHODS: This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve. RESULTS: A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant. CONCLUSION: This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery.

BACKGROUND: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. PURPOSE: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. RESULTS: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, -2.4°± 2.2° and -3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (ß = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). CONCLUSION: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Malrotated lateral knee radiographs do not allow for a proper assessment of medial or lateral posterior tibial slope.

PURPOSE: The aim of this study was to investigate whether malrotation of lateral knee radiographs influences posterior tibial slope (PTS) measurements. METHODS: Lateral knee radiographs of all patients who underwent knee surgery at a single institution between June 2022 and January 2023 and received multiple lateral knee radiographs were included. Radiographs were categorised as malrotated lateral knee radiographs or lateral knee radiographs based on the radiographic distance between the medial and lateral posterior femoral condyles. Medial PTS (MPTS) and lateral PTS (LPTS) were evaluated on malrotated lateral knee radiographs and lateral knee radiographs and compared using the paired t test. Intra- and interrater reliability between four raters were assessed for MPTS and LPTS measurements. RESULTS: A total of 92 lateral knee radiographs (46 pairs of malrotated lateral knee radiographs and lateral knee radiographs; 50.0% right side) from 46 patients (33.2 ± 12.4 years, 69.6% male) were included. Mean posterior femoral condyle distance in malrotated lateral knee radiographs was 8.1 ± 4.4 mm. Overall, MPTS and LPTS were significantly higher on malrotated lateral knee radiographs versus lateral knee radiographs (medial: 10.5 ± 3.2° vs. 9.7 ± 3.5°, p < 0.05; lateral: 10.6 ± 3.4° vs. 9.7 ± 3.3°, p < 0.05). Mean absolute difference between MPTS and LPTS on malrotated lateral knee radiographs versus lateral knee radiographs were |1.9| ± |1.5|° and |2.0| ± |1.8|°, respectively. Intrarater reliability was 'moderate' and interrater reliability was 'good' for both MPTS and LPTS. CONCLUSION: Malrotation of lateral knee radiographs led to a significant distortion of both the MPTS and LPTS. In clinical practice, attention should be placed on the (mal)rotation of lateral knee radiographs, especially in patients for whom a slope-correcting osteotomy is being discussed. LEVEL OF EVIDENCE: Level IV.